The Don Mario deposit was probably worked by the Jesuits during the 18th century. During the 1990s, various companies explored the area and encountered mineralization in various drill holes. In January 2002, Compania Minera del Sur S.A. (Comsur), the largest privately-owned mining company in Bolivia at the time, acquired a controlling interest in Orvana and managed the construction and initial start-up of the Lower Mineralized Zone (LMZ) in 2003. Orvana assumed the management of the mine in September 2005. The mine produced more than 400,000 ounces of gold and generated more than US$135 million cash flow before it was depleted in the fourth quarter of fiscal 2009.

A few years before depletion of the LMZ, Orvana followed up on some historical sample anomalies and drilling, and by 2008 delineated the Las Tojas shear-zone gold deposit. To try to maintain the past levels of annual gold production, a generator and ball mill were commissioned in June 2009 to increase throughput to about 2,000 tonnes per day at the Don Mario Mine. This production could extend the Don Mario mine life to 2010, though production will be less than previous years. The potential to discover more gold on trend with the Las Tojas deposit is high and exploration is ongoing.

In May 2009, the Board approved development of the Don Mario Upper Mineralized Zone (UMZ), following completion of a detailed operational study that incorporates a feasibility summary based on an updated mine model. The UMZ mine plan contemplates a flotation plant with a mill throughput of 1,900 tonnes per day over a nine year mine life. The goal is to achieve production towards the end of fiscal 2010. The UMZ comprises a small hill devoid of vegetation that overlies the LMZ